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* [Bug c++/94568] New: template specialization of equivalent nontype template argument involving member pointer considered distinct
@ 2020-04-12 20:19 msebor at gcc dot gnu.org
2020-04-15 15:49 ` [Bug c++/94568] " msebor at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: msebor at gcc dot gnu.org @ 2020-04-12 20:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94568
Bug ID: 94568
Summary: template specialization of equivalent nontype template
argument involving member pointer considered distinct
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
I believe the two definitions of XB below are the same and should be accepted.
GCC for some reason not evident from the error message treats them as distinct.
$ cat t.C && gcc -O2 -S -Wall -std=c++2a t.C
struct A;
typedef int A::*MemPtr;
struct B { MemPtr p; };
static constexpr MemPtr mp { };
template <B> struct X { };
typedef X<B{{MemPtr{ }}}> XB;
typedef X<B{{mp}}> XB;
t.C:11:27: error: conflicting declaration ‘typedef struct X<B{-1}> XB’
11 | typedef X<B{{mp}}> XB;
| ^~
t.C:10:27: note: previous declaration as ‘typedef struct X<B{-1}> XB’
10 | typedef X<B{{MemPtr{ }}}> XB;
| ^~
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94568] template specialization of equivalent nontype template argument involving member pointer considered distinct
2020-04-12 20:19 [Bug c++/94568] New: template specialization of equivalent nontype template argument involving member pointer considered distinct msebor at gcc dot gnu.org
@ 2020-04-15 15:49 ` msebor at gcc dot gnu.org
2020-04-15 16:51 ` ensadc at mailnesia dot com
2020-11-16 22:17 ` redi at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: msebor at gcc dot gnu.org @ 2020-04-15 15:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94568
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Another test case, this one not involving pointers. Somehow the form of the
initializer (= 0 vs { }) makes a difference.
$ cat t.C && gcc -O2 -c -Wall -std=c++2a t.C
template <C> struct D { };
constexpr const int i0 = 0;
constexpr const int i_{ };
static_assert (i0 == i_);
typedef D<C{ { 0, 1 } }> DC01;
typedef D<C{ { i0, 1 } }> DC01;
typedef D<C{ { i_, 1 } }> DC01;
t.C:11:28: error: conflicting declaration ‘typedef struct D<C{int [2]{0, 1}}>
DC01’
11 | typedef D<C{ { i_, 1 } }> DC01;
| ^~~~
t.C:10:28: note: previous declaration as ‘typedef struct D<C{int [2]{0, 1}}>
DC01’
10 | typedef D<C{ { i0, 1 } }> DC01;
| ^~~~
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94568] template specialization of equivalent nontype template argument involving member pointer considered distinct
2020-04-12 20:19 [Bug c++/94568] New: template specialization of equivalent nontype template argument involving member pointer considered distinct msebor at gcc dot gnu.org
2020-04-15 15:49 ` [Bug c++/94568] " msebor at gcc dot gnu.org
@ 2020-04-15 16:51 ` ensadc at mailnesia dot com
2020-11-16 22:17 ` redi at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: ensadc at mailnesia dot com @ 2020-04-15 16:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94568
ensadc at mailnesia dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ensadc at mailnesia dot com
--- Comment #2 from ensadc at mailnesia dot com ---
struct C { int a[2]; };
template <C> struct D { };
constexpr int i_{ };
typedef D<C{ { i_, 1 } }> DC01;
void f(DC01) {}
The name of `f` is mangled as `_Z1f1DIXtl1CtlA2_iLKi0ELi1EEEEE`. The `LKi0E`
part seems to suggest that the element corresponding to `i_` has type `const
int`, where it should be a plain `int`.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94568] template specialization of equivalent nontype template argument involving member pointer considered distinct
2020-04-12 20:19 [Bug c++/94568] New: template specialization of equivalent nontype template argument involving member pointer considered distinct msebor at gcc dot gnu.org
2020-04-15 15:49 ` [Bug c++/94568] " msebor at gcc dot gnu.org
2020-04-15 16:51 ` ensadc at mailnesia dot com
@ 2020-11-16 22:17 ` redi at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: redi at gcc dot gnu.org @ 2020-11-16 22:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94568
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |ABI
Status|UNCONFIRMED |NEW
Last reconfirmed| |2020-11-16
Ever confirmed|0 |1
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Adding the ABI keyword, since this seems to involve a mangling bug.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-11-16 22:17 UTC | newest]
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2020-04-12 20:19 [Bug c++/94568] New: template specialization of equivalent nontype template argument involving member pointer considered distinct msebor at gcc dot gnu.org
2020-04-15 15:49 ` [Bug c++/94568] " msebor at gcc dot gnu.org
2020-04-15 16:51 ` ensadc at mailnesia dot com
2020-11-16 22:17 ` redi at gcc dot gnu.org
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